SENR6205-01
16 Page, (Dimensions: 24 inches x 34 inches)
ONE POSITION
TWO POSITION
THREE POSITION
VENTED
PRESSURIZED
RETURN ABOVE FLUID LEVEL
RETURN BELOW FLUID LEVEL
LINES CROSSING
LINES JOINING
TWO-WAY
THREE-WAY
FOUR-WAY
SPRING
CONTROL VALVES
RESTRICTION
LINE RESTRICTION
(FIXED)
2-SECTION PUMP
MAIN
AUX.
SPRING
(ADJUSTABLE)
VARIABILITY
LINE RESTRICTION
(VARIABLE)
LINE RESTRICTION
VARIABLE and PRESSURE
COMPENSATED
PRESSURE
COMPENSATION
PUMP: VARIABLE and
PRESSURE COMPENSATED
ENERGY TRIANGLES
HYDRAULIC PNEUMATIC
MEASUREMENT
PRESSURE
TEMPERATURE
FLOW
ROTATING SHAFTS
UNIDIRECTIONAL BIDIRECTIONAL
PUSH-PULL LEVER PEDALGENERAL MANUAL PUSH BUTTON SPRING
MANUAL CONTROL SYMBOLS
HYDRAULIC MOTORS
FIXED
DISPLACEMENT
VARIABLE DISPLACEMENT
NON-COMPENSATED
UNIDIRECTIONAL
BIDIRECTIONAL
HYDRAULIC PUMPS
FLUID STORAGE RESERVOIRS
CROSSING AND JOINING LINES
VALVE ENVELOPES
VALVE PORTS
BASIC COMPONENT SYMBOLS
FLUID CONDITIONER
PUMP or MOTOR
FLUID POWER SYMBOLS
FIXED
DISPLACEMENT
VARIABLE DISPLACEMENT
NON-COMPENSATED
UNIDIRECTIONAL
BIDIRECTIONAL
VALVES
PILOT CONTROL SYMBOLS
RELEASED PRESSURE
EXTERNAL RETURN
INTERNAL RETURN
REMOTE SUPPLY PRESSURE
SIMPLIFIED
COMPLETE
INTERNAL
SUPPLY PRESSURE
ACCUMULATORS
SPRING LOADED
GAS CHARGED
SOLENOID
or MANUAL
SOLENOID
and PILOT
SOLENOID and
PILOT or MANUAL
COMBINATION CONTROLS
SOLENOID
SERVO
THERMAL
DETENT
HYDRAULIC AND PNEUMATIC CYLINDERS
DOUBLE ACTING
SINGLE ACTING
BASIC
SYMBOL
SPRING
LOADED
CHECK VALVES
TWO
POSITION
INFINITE
POSITIONING
FLOW IN ONE
DIRECTION
FLOW ALLOWED IN
EITHER DIRECTION
THREE
POSITION
CROSS
FLOW
PARALLEL
FLOW
INTERNAL PASSAGEWAYS
NORMAL POSITION
A B
P T
A B
P T
SHIFTED POSITION
INFINITE POSITION
CONTROL VALVES
ATTACHMENT
MANUAL SHUTOFF
SHUTTLE PILOT
CONTROLLED
Hydraulic Symbols (Electrical)
Electrical Symbols Table
325-AG135 PK-14
Circuit Identification
Number
Wire Color
Wire Gauge
Harness identification code
This example indicates
wire 135 in harness "AG".
325-PK-14
Wire Gauge
Wire Color
Circuit Number
Identification
Wire Number Identification Codes
Current Standard
Previous Standard
Electrical Schematic Example
Hydraulic Schematic Example
325-PK
Wire Color
Circuit Number
Identification
B
A
Wire
Wire
(EXAMPLE VALVE)
Current Standard
Transducer
(Fluid)
Transducer
(Gas / Air)
G
Generator
Electrical Wire
Pressure Switch
M
Electric Motor
Pressure Switch
(Adjustable)
Temperature Switch
T
Pressure
Symbol
Temperature
Symbol
Level
Symbol
Flow
Symbol
Electrical Symbols (Electrical)
Single Action
SENR6205-01
September 2006
350 & 350L Excavators
Hydraulic System - Attachment
350:
7RK1-324
8HK1-UP
2ZL1-170
350L:
9DK1-212
3ML1-684
9FL1 -419
©
2006 Caterpillar
All Rights Reserved
Printed in U.S.A.
SENR6205-01
16 Page, Color 2, (Dimensions: 24 inches x 34 inches)
THIS SCHEMATIC IS FOR THE 350 AND 350L
Components are shown installed on a fully operable machine with the key and engine off.
Refer to the appropriate Service Manual for Troubleshooting, Specifications and Systems Operations
Item No.
1
2
ATTACHMENT COMPONENTS
Component
Relief Valve
Pilot Valve ( Foot Opertated)
1
2
1
2
XA
PD
JL3JLJR3
JR1
JR2
TRT
TLP
TLA1
TLA2
MA
G
A
ST2
TRA2
TRA1
TRP
TLT
(CLOSE)
Pi
R
T1
L'
L'
BR
BR
MB MA
M
MB
A'B'
PR
PG
E
F
D
SH
XB
MA
T1
A'
SH
D
F
E
P
T
M2
M1
B'
B
P1
T
P2
Pi
Dr
A
T2
X
T2
A2
DR5
JPd
Jd
JPg
JP1
(OPEN)
(UP)
JL2JL4JR4
Pi1 Pi2 Pi3
aR3
DR1
aL3
bR3
DR2
DR3
bL3
aL1aR1
bL4
aL4
bR1
PFPR
SV1
bL1
PP
TOUT
PIN
PG
SV2
LS2
DR4
AL4
BR1
R2
AR1
Pi4
BL1 AL1
IMP2
PSW
PTA
TRBM1
DS
LS1AR3BR3
AL3
BL3
AL2
PG
PR
BL4
bL2
dR1
A3
A4
A5
A1
S
P
B1
T
B2
B3
BSIN
BM2
IMP1
T
T
P
SD1
P
aL2
R1
A
B4
B5
Z
Y
IN
OUT
(DOWN)(CLOSE)
(OPEN)
M
MA
Pi2
B
Pi1
T
A
HL1
HL2
PD
P1
T
P2Pi
Dr
P
X
PS1
LS1
S1Dr1 Dr2
LS2
BL2
PS
SA2
M2
P2
P1
M1
SA1
UP
MAIN CONNECTOR LINE
PILOT LINE
DRAIN LINE
HYDRAULIC SCHEMATIC - ATTACHMENT
113-6527
C75050
HAMMER
BUCKET
CYLINDER
STICK
CYLINDER
BOOM
CYLINDERS
RIGHT
TRAVEL
LEFT
TRAVEL
SWING
SWIVEL
TRAVEL ALARM
PRESSURE SW
PUMP CONTROL
PRESSURE SW
PUMP CONTROL
PRESSURE SW
SWING 2 STEP
POWER CONTROL
SOLENOID VALVE
ON : H MODE
OFF : L,S MODE
TRAVEL(R)TRAVEL(L)
BUCKET STICK
BOOM
HAMMER
OPEN OPEN
CLOSE CLOSE
FWD FWD
REV REV
DOWN
FRONT REAR
SWING PUMP
BUCKET BOOM SWING STICK
TRAVEL (L)
TRAVEL (R)
This Attachment Schematic is intended to
be used in conjunction with the Standard
Hydraulic Schematic in this Service Manual.
